Flow battery cleaning apparatus, cleaning method, and cleaning system

Abstract

A flow battery cleaning apparatus, cleaning method, and cleaning system. A flow battery comprises: a positive electrode electrolyte tank, a negative electrode electrolyte tank, and a stack unit. The positive electrode electrolyte tank and the stack unit form a positive electrode circulation loop, and the negative electrode electrolyte tank and the stack unit form a negative electrode circulation loop. The flow battery cleaning apparatus comprises: a detection apparatus, a first foreign matter removal apparatus, and a second foreign matter removal apparatus, the detection apparatus comprising a first detection apparatus. The first detection apparatus is configured to detect whether foreign matter is present in the stack unit; the first foreign matter removal apparatus is configured to adjust the pressure of the positive electrode circulation loop; and the second foreign matter removal apparatus is configured to adjust the pressure of the negative electrode circulation loop.

Description

Liquid flow battery cleaning device, cleaning method and system Technical Field

[0001] This article relates to, but is not limited to, the field of electrochemical energy storage, and in particular to a flow battery cleaning device, cleaning method, and system. Background Art

[0002] With the development of society and the economy, the demand for new energy sources continues to grow, driving the development of the energy storage industry. Flow batteries achieve the mutual conversion of electrical energy and chemical energy through reversible redox reactions (i.e., reversible changes in valence states) between the active substances in the positive and negative electrolytes. Due to their excellent stability and safety, flow batteries have become a mainstream technology solution in the energy storage field.

[0003] The inventors of the present application have discovered through research that the stack units of flow batteries are easily clogged by foreign matter such as crystals.

[0004] Summary of the Invention

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] The embodiments of the present application provide a liquid flow battery cleaning device, a cleaning method, and a system, which can solve the problem that the stack units of the liquid flow battery are easily clogged by foreign matter such as crystals.

[0007] In the first aspect, an embodiment of the present application provides a liquid flow battery cleaning device, wherein the liquid flow battery includes: a positive electrode liquid tank, a negative electrode liquid tank and a battery stack unit, the positive electrode liquid tank and the battery stack unit form a positive electrode circulation loop, and the negative electrode liquid tank and the battery stack unit form a negative electrode circulation loop; it is characterized in that the liquid flow battery cleaning device includes: a detection device, a first foreign matter removal device and a second foreign matter removal device, the detection device includes a first detection device; the first detection device is configured to detect whether there is foreign matter in the battery stack unit; the first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop; the second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop.

[0008] In an exemplary embodiment, the first detection device is configured to detect whether there is a foreign object in the battery stack unit every first time period.

[0009] In an exemplary embodiment, the detection device further includes a second detection device and a third detection device; the second detection device is configured to detect a first pressure value of the positive electrode circulation loop, and the third detection device is configured to detect a second pressure value of the negative electrode circulation loop; the first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop to a third pressure value when the first pressure value is less than a first threshold value; the third pressure value is greater than the first pressure value and less than the first threshold value; the second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop to a fourth pressure value when the second pressure value is less than the first threshold value; the fourth pressure value is greater than the second pressure value and less than the first threshold value.

[0010] In an exemplary embodiment, the liquid flow battery cleaning device further includes a first switch and a second switch, wherein the first switch is arranged on the positive electrode circulation loop and is configured to open or close the positive electrode circulation loop; the second switch is arranged on the negative electrode circulation loop and is configured to open or close the negative electrode circulation loop.

[0011] In an exemplary embodiment, the liquid flow battery cleaning device also includes a first filter device and a second filter device; the first filter device is connected to the positive electrode circulation loop and is configured to prevent the foreign matter from entering the positive electrode liquid tank; the second filter device is connected to the negative electrode circulation loop and is configured to prevent the foreign matter from entering the negative electrode liquid tank.

[0012] In an exemplary embodiment, the detection device further includes a fourth detection device, which is configured to detect whether the working state of the flow battery is normal before the first detection device detects whether there is a foreign object in the battery stack unit.

[0013] In an exemplary embodiment, the liquid flow battery cleaning device further includes a display device; the display device is configured to display whether the working status of the liquid flow battery is normal based on the detection result of the fourth detection device.

[0014] In an exemplary embodiment, the flow battery cleaning device further includes an automatic control device; the automatic control device is configured to control the operation of the first foreign matter removal device, the second foreign matter removal device, and the display device according to the detection result of the detection device.

[0015] In the second aspect, an embodiment of the present application also provides a method for cleaning a liquid flow battery, wherein the liquid flow battery includes: a positive electrode liquid tank, a negative electrode liquid tank and a stack unit, wherein the positive electrode liquid tank and the stack unit form a positive electrode circulation loop, and the negative electrode liquid tank and the stack unit form a negative electrode circulation loop; the method includes: using a first detection device to detect whether there is foreign matter in the stack unit; using a first foreign matter removal device to remove foreign matter located in the positive electrode circulation loop, wherein the first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop; and using a second foreign matter removal device to remove foreign matter located in the negative electrode circulation loop, wherein the second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop.

[0016] In a third aspect, an embodiment of the present application further provides a liquid flow battery cleaning system, comprising a liquid flow battery and the liquid flow battery cleaning device as described above.

[0017] The liquid flow battery cleaning device provided in the embodiment of the present application can increase the flushing force of the electrolyte in its own circulation loop by adjusting the pressure of the positive electrode circulation loop through the first foreign matter removal device and the pressure of the negative electrode circulation loop by the second foreign matter removal device when the first detection device detects the presence of foreign matter in the stack unit, thereby cleaning out the foreign matter in the stack unit. The liquid flow battery cleaning device provided in the embodiment of the present application can timely detect and clean foreign matter such as crystals in the stack unit, reduce the probability of blockage of the stack unit, help ensure the long-term stable operation of the liquid flow battery, and reduce the maintenance cost of the liquid flow battery. It solves the problem that the stack unit of the liquid flow battery is easily blocked by foreign matter such as crystals.

[0018] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. Other advantages of the present application can be realized and obtained by the solutions described in the description and the drawings.

[0019] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0021] FIG1 is a schematic diagram of a flow battery;

[0022] FIG2 is a schematic diagram of a flow battery cleaning device in an exemplary embodiment;

[0023] FIG3 is a schematic diagram of a cleaning process using the flow battery cleaning device shown in FIG2 in an exemplary embodiment. DETAILED DESCRIPTION

[0024] This application describes multiple embodiments, but this description is exemplary rather than restrictive, and it will be apparent to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described herein. Although many possible feature combinations are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0025] The embodiments of the present application include and contemplate combinations of features and elements known to those of ordinary skill in the art. The embodiments, features, and elements disclosed in this application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in this application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the appended claims and their equivalents, the embodiments are not subject to other limitations. In addition, various modifications and changes may be made within the scope of protection of the appended claims.

[0026] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps in the specific order described. As will be understood by those skilled in the art, other orders of steps are also possible. Therefore, the specific order of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to performing their steps in the order written, and those skilled in the art can readily understand that these orders can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0027] A flow battery is a high-performance storage battery that separates and circulates the positive and negative electrolytes. The electrolyte contains active substances, which flow through the positive and negative electrolytes and undergo reversible redox reactions, enabling the flow battery to complete the charging and discharging process. Depending on the active substances contained in the electrolyte, flow batteries can be divided into: all-vanadium flow batteries, iron-chromium flow batteries, zinc-bromine flow batteries, sodium polysulfide / bromine flow batteries, and zinc / nickel flow batteries. As an electrochemical energy storage technology, flow batteries are characterized by high capacity, wide application range, and long cycle life.

[0028] FIG1 is a schematic diagram of a liquid flow battery. As shown in FIG1 , the liquid flow battery includes a cathode liquid tank 100, a cathode liquid tank 200, and a stack unit 300. The cathode liquid tank 100 contains a cathode electrolyte, which circulates between the cathode liquid tank 100 and the stack unit 300 via a cathode pipe 101. The flow direction of the cathode electrolyte can be shown by the arrow direction of the cathode pipe 101 in FIG1 . The cathode liquid tank 200 contains a cathode electrolyte, which circulates between the cathode liquid tank 200 and the stack unit 300 via a cathode pipe 201. The flow direction of the cathode electrolyte can be shown by the arrow direction of the cathode pipe 201 in FIG1 . A separator 301 can be provided in the stack unit 300 to prevent mixing of the cathode electrolyte and the cathode electrolyte. The stack unit 300 has a positive electrode (+) and a negative electrode (-), which can be connected to an external power source or load to achieve charging and discharging. The electrolyte will undergo oxidation or reduction reactions in the process of flowing through the stack unit 300. During the charging process of the flow battery, the positive electrode electrolyte undergoes an oxidation reaction to increase the valence of the active substance, and the negative electrode electrolyte undergoes a reduction reaction to reduce the valence of the active substance. The discharge process is the opposite. Since the flow battery can achieve spatial separation of the electrochemical reaction site (stack unit) and the energy storage active material, the battery power and capacity design are relatively independent, so it is suitable for large-scale energy storage systems such as wind power generation and photovoltaic power generation.

[0029] The inventors of this application have discovered in practice that liquid flow batteries generate a large amount of heat during operation, which increases the temperature of the electrolyte. At high temperatures, the electrolyte crystallizes, leading to blockage of the flow channels within the stack cells. Taking all-vanadium liquid flow batteries as an example, vanadium ions in the electrolyte generate crystals such as vanadium pentoxide at high temperatures. These crystals can easily block the flow channels within the stack cells, seriously affecting the service life of the stack cells and the operating efficiency of the liquid flow battery. Once the flow channels of the stack cells are clogged, they can only be cleaned manually, which is costly and inefficient, and results in a poor user experience.

[0030] The present application provides a flow battery cleaning device, the flow battery comprising: a cathode liquid tank, a cathode liquid tank, and a stack unit, wherein the cathode liquid tank and the stack unit form a cathode circulation loop, and the cathode liquid tank and the stack unit form a cathode circulation loop; the flow battery cleaning device comprises: a detection device, a first foreign matter removal device, and a second foreign matter removal device, wherein the detection device comprises a first detection device;

[0031] The first detection device is configured to detect whether there is foreign matter in the stack unit;

[0032] The first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop;

[0033] The second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop.

[0034] The liquid flow battery cleaning device provided in the embodiment of the present application, when the first detection device detects the presence of foreign matter in the battery stack unit, adjusts the pressure of the positive electrode circulation loop through the first foreign matter removal device, and adjusts the pressure of the negative electrode circulation loop through the second foreign matter removal device, thereby increasing the flushing force of the electrolyte in its own circulation loop, thereby clearing out foreign matter in the battery stack unit. The liquid flow battery cleaning device provided in the embodiment of the present application can promptly detect and clean foreign matter such as crystals in the battery stack unit, which can reduce the probability of blockage in the battery stack unit, help ensure the long-term stable operation of the liquid flow battery, and reduce the maintenance cost of the liquid flow battery.

[0035] In an exemplary embodiment, the first detection device is configured to detect whether there is a foreign object in the stack unit every first time period.

[0036] In this embodiment, the first detection device can be configured to detect the stack unit once every first time period. By setting the length of the first time period, the operating frequency of the first detection device can be controlled, thereby ensuring that the first detection device does not operate continuously while promptly detecting foreign objects in the stack unit, thereby contributing to energy conservation and ensuring the long-term stable operation of the first detection device. The length of the first time period can be set as needed, and this application does not impose any restrictions on this.

[0037] In an exemplary embodiment, the first detection device can be, for example, an ultrasonic detector, which can detect whether there are foreign objects in the battery stack unit and calculate the actual location of the foreign objects, thereby facilitating the control of the operation of the first foreign object removal device and / or the second foreign object removal device to flush out the foreign objects in the battery stack unit.

[0038] In an exemplary embodiment, the first detection device can be, for example, a pressure detection device such as a pressure sensor. When foreign matter is present in the flow path of the battery stack unit, the flow of the electrolyte will be affected, causing the pressure value in the positive electrode circulation loop or the negative electrode circulation loop to change. The presence of the foreign matter can be determined by detecting the change in the pressure value in the positive electrode circulation loop or the negative electrode circulation loop. In an exemplary embodiment, the relationship between the influence of parameters such as the size and position of the foreign matter on the change in the pressure value at different positions in the circulation loop can be established in advance, and at least one pressure detection device is set at at least one position in a single circulation loop. When a change in the pressure value at the corresponding position in the circulation loop is detected, the first foreign matter removal device or the second foreign matter removal device is controlled to operate to impact and remove the foreign matter in the battery stack unit.

[0039] In an exemplary embodiment, the first detection device may be, for example, an electrolyte flow rate detection device. When foreign matter exists in the flow channel of the battery stack unit, the flow of the electrolyte will be affected, causing the flow rate of the electrolyte in the positive circulation loop or the negative circulation loop to change. The presence of foreign matter can be determined by detecting the change in the liquid flow rate in the positive circulation loop or the negative circulation loop. In an exemplary embodiment, the relationship between the influence of parameters such as the size and position of foreign matter on the change in the liquid flow rate at different positions in the circulation loop can be established in advance, and at least one flow rate detection device is set at at least one position in a single circulation loop, so that when a change in the flow rate of the liquid at the corresponding position in the circulation loop is detected, the first foreign matter removal device or the second foreign matter removal device is controlled to work, thereby impacting the foreign matter in the battery stack unit. In actual applications, the type of the first detection device and the method of detecting foreign matter can be selected according to actual conditions, and this application does not impose any restrictions on this.

[0040] In an exemplary embodiment, the detection device further includes a second detection device and a third detection device; the second detection device is configured to detect a first pressure value of the positive electrode circulation loop, and the third detection device is configured to detect a second pressure value of the negative electrode circulation loop. The first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop to a third pressure value when the first pressure value is less than a first threshold value; the third pressure value is greater than the first pressure value and less than the first threshold value. The second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop to a fourth pressure value when the second pressure value is less than the first threshold value; the fourth pressure value is greater than the second pressure value and less than the first threshold value.

[0041] In this embodiment, a first threshold value can be pre-set. The first threshold value can be the product of the maximum pressure value that the stack unit can withstand and the first coefficient. The first coefficient can be greater than 0 and less than or equal to 1. For example, the first coefficient can be 1, in which case the first threshold value is the maximum pressure value that the stack unit can withstand. In other embodiments, the first coefficient can be a value such as 0.8 or 0.9, and the first threshold value can be less than the maximum pressure value that the stack unit can withstand. This ensures that no damage is caused to the stack unit when adjusting the pressure value of the positive electrode circulation loop or the pressure value of the negative electrode circulation loop. The first threshold value can be set according to actual needs, and this application does not impose any restrictions on this.

[0042] In an exemplary embodiment, the second detection device may be, for example, a pressure detection device such as a pressure sensor provided in the positive electrode circulation loop, and may detect a first pressure value of the positive electrode circulation loop. The third detection device may be, for example, a pressure detection device such as a pressure sensor provided in the negative electrode circulation loop, and may detect a second pressure value of the negative electrode circulation loop. This application does not limit the types of the second detection device and the third detection device.

[0043] In an exemplary embodiment, the third pressure value and the fourth pressure value are equal.

[0044] In an exemplary embodiment, the first foreign matter removal device can gradually adjust the pressure value of the positive electrode circulation loop in stages. In the process of adjusting the first pressure value to the third pressure value, a plurality of incremental step values ​​can be divided, and the pressure value of the positive electrode circulation loop is adjusted to different step value levels in order from small to large, and each step value is maintained for a period of time to ensure that the pressure value of the positive electrode circulation loop is gradually and steadily increased. For example, the first pressure value is 100Pa and the third pressure value is 150Pa. The first step value can be set to 120Pa and the second step value can be set to 140Pa. In the process of adjusting the first pressure value to the third pressure value, the first pressure value of the positive electrode circulation loop is first adjusted from 100Pa to the first step value of 120Pa, maintained for 30 seconds, and then the pressure value of the positive electrode circulation loop is adjusted to the second step value of 140Pa. After maintaining for 30 seconds, the pressure value of the positive electrode circulation loop is adjusted to the third pressure value of 150Pa, thereby gradually adjusting the pressure value of the positive electrode circulation loop. In the process of adjusting the first pressure value to the third pressure value, if it is detected that the foreign matter in the stack unit disappears, the pressure value of the positive electrode circulation loop can be adjusted back to the first pressure value. For example, if the foreign matter is found to be washed away within 30 seconds of maintaining the pressure value of the positive electrode circulation loop at the first step value of 120Pa, the positive electrode circulation loop can be adjusted back to the first pressure value of 100Pa without the need to adjust the larger step value. The above numerical examples are only for schematic illustration and do not represent the actual numerical level. The division of the step value and the holding time of each step value can be set as needed, and this application does not impose any restrictions on this. The working process of the second foreign matter removal device can be similar to that of the first foreign matter removal device and will not be repeated here.

[0045] In an exemplary embodiment, a first functional relationship between the pressure change and time can be set in advance, and the first foreign matter removal device can adjust the first pressure value to a third pressure value according to the set first functional relationship, so as to control the flushing force of the electrolyte during the pressure adjustment process. For example, the flushing force of the electrolyte can be controlled to be different at different stages of the first function, thereby better controlling the flushing force on foreign matter and improving the foreign matter removal effect. In an exemplary embodiment, the first functional relationship between the pressure change △P and time t can be set in advance as a linear function, a quadratic function, or a combination of different functional relationships. In actual applications, appropriate functional relationships and specific parameters can be set as needed, and this application does not impose any restrictions on this. The pressure adjustment process of the second foreign matter removal device can refer to the description of the first foreign matter removal device and will not be repeated here.

[0046] In an exemplary embodiment, the first foreign matter removal device may be, for example, an electric valve that can be controlled to open and close to adjust the pressure of the positive electrode circulation loop. Alternatively, the first foreign matter removal device may be a variable frequency water pump that can adjust the pressure of the positive electrode circulation loop by adjusting the flow rate of the electrolyte within the positive electrode circulation loop. The type of the second foreign matter removal device can be described with reference to the first foreign matter removal device and will not be further described here. The types of the first and second foreign matter removal devices can be set as needed and are not limited by this application.

[0047] In an exemplary embodiment, the liquid flow battery cleaning device also includes a first filter device and a second filter device, the first filter device is connected to the positive electrode circulation loop and is configured to prevent the foreign matter from entering the positive electrode liquid tank; the second filter device is connected to the negative electrode circulation loop and is configured to prevent the foreign matter from entering the negative electrode liquid tank.

[0048] In this embodiment, by providing a first filter and a second filter, flushed foreign matter is prevented from entering the cathode and cathode liquid tanks. After flushing away the foreign matter, only the first and second filters need to be cleaned to remove the foreign matter, eliminating the need to disassemble the flow battery, thus facilitating stable, long-term operation of the flow battery.

[0049] In an exemplary embodiment, the first filter device and the second filter device may be, for example, Y-type filters, and the present application does not limit the types of the filter devices.

[0050] In an exemplary embodiment, the liquid flow battery cleaning device also includes a first switch and a second switch, wherein the first switch is arranged on the positive electrode circulation loop and is configured to open or close the positive electrode circulation loop; the second switch is arranged on the negative electrode circulation loop and is configured to open or close the negative electrode circulation loop.

[0051] In an exemplary embodiment, the flow battery further comprises: a positive electrode conduit, a positive electrode liquid pump, a negative electrode conduit, and a negative electrode liquid pump;

[0052] The cathode pipeline is connected to the cathode liquid tank and the battery stack unit, and is configured to form a cathode circulation loop between the cathode liquid tank and the battery stack unit;

[0053] A cathode liquid pump is connected to the cathode pipeline and is configured to circulate the cathode electrolyte between the cathode liquid tank and the stack unit;

[0054] The negative electrode pipeline is connected to the negative electrode liquid tank and the battery stack unit, and is configured to form a loop between the negative electrode liquid tank and the battery stack unit;

[0055] The negative electrode liquid pump is connected to the negative electrode pipeline and is configured to allow the negative electrode electrolyte to circulate between the negative electrode liquid tank and the stack unit.

[0056] In an exemplary embodiment, the positive electrode liquid pump and the negative electrode liquid pump can have the function of regulating the pressure and flow rate of the electrolyte, for example, they can be variable frequency water pumps. The embodiment of the present application does not limit the types of the positive electrode liquid pump and the negative electrode liquid pump.

[0057] In an exemplary embodiment, the stack unit is configured to provide electrochemical reaction sites for the positive electrode electrolyte and the negative electrode electrolyte, respectively.

[0058] In an exemplary embodiment, the first switch is provided on the positive electrode pipeline between the positive electrode liquid pump and the positive electrode liquid tank, and is configured to open or close the positive electrode pipeline; the second switch is provided on the negative electrode pipeline between the negative electrode liquid pump and the negative electrode liquid tank, and is configured to open or close the negative electrode pipeline.

[0059] In an exemplary embodiment, the first switch and the second switch may be electric valves, which is not limited in the present application.

[0060] In this embodiment, by providing a first switch, the positive electrode pipeline can be closed when the positive electrode liquid pump fails, preventing the positive electrode electrolyte from flowing out of the positive electrode liquid tank, facilitating replacement or repair of the positive electrode liquid pump. By providing a second switch, the negative electrode pipeline can be closed when the negative electrode liquid pump fails, preventing the negative electrode electrolyte from flowing out of the negative electrode liquid tank, facilitating replacement or repair of the negative electrode liquid pump.

[0061] In an exemplary embodiment, the detection device further includes a fourth detection device, which is configured to detect whether the working state of the flow battery is normal before the first detection device detects whether there is a foreign object in the battery stack unit.

[0062] In an exemplary embodiment, the flow battery cleaning device further includes a display device configured to display whether the flow battery is operating normally based on the detection result of the fourth detection device. In an exemplary embodiment, the display device may only display the abnormal operating status of the flow battery. The display device may include a display screen.

[0063] In an exemplary embodiment, the flow battery cleaning device further includes a fifth detection device, which is configured to detect whether the working state of the battery stack unit is normal before the first detection device detects whether there is foreign matter in the battery stack unit.

[0064] In an exemplary embodiment, the display device is further configured to display whether the working state of the battery stack unit is normal according to the detection result of the fifth detection device. In an exemplary embodiment, the display device may only display when the working state of the battery stack unit is abnormal.

[0065] In an exemplary embodiment, the display device is further configured to display the working status of the flow battery cleaning device and the working status of the flow battery, which is not limited in this application.

[0066] In an exemplary embodiment, the flow battery cleaning device further includes an automatic control device, which is configured to control the operation of the first foreign matter removal device, the second foreign matter removal device, and the display device according to the detection result of the detection device.

[0067] Figure 2 is a schematic diagram of a flow battery cleaning device in an exemplary embodiment. As shown in Figure 2, the flow battery includes a cathode liquid tank 1, a cathode liquid tank 7, and a stack unit 5. The cathode liquid tank 1 has a liquid outlet and a liquid inlet, and the stack unit 5 has a cathode liquid inlet and a cathode liquid outlet. A cathode liquid flow path is provided between the cathode liquid inlet and the cathode liquid outlet. A cathode pipe 4 is provided between the cathode liquid tank 1 and the stack unit 5. The cathode pipe 4 connects the liquid outlet of the cathode liquid tank 1 to the cathode liquid inlet of the stack unit 5, and also connects the cathode liquid outlet of the stack unit 5 to the liquid inlet of the cathode liquid tank 1, forming a cathode circulation loop between the cathode liquid tank 1 and the stack unit 5. A positive electrode liquid pump 3 is provided on the positive electrode pipe 4 between the liquid outlet of the positive electrode liquid tank 1 and the positive electrode liquid inlet of the stack unit 5. Under the action of the positive electrode liquid pump 3, the positive electrode electrolyte circulates between the positive electrode liquid tank 1, the positive electrode pipe 4, and the positive electrode liquid flow path of the stack unit 5. The direction of the hollow arrow on the positive electrode pipe 4 is the direction of the positive electrode electrolyte flow. The negative electrode liquid tank 7 also has a liquid outlet and a liquid inlet. The stack unit 5 has a negative electrode liquid inlet and a negative electrode liquid outlet. The negative electrode liquid flow path is between the negative electrode liquid inlet and the negative electrode liquid outlet. A negative electrode pipe 10 is provided between the negative electrode liquid tank 7 and the stack unit 5. The negative electrode pipe 10 connects the liquid outlet of the negative electrode liquid tank 7 to the negative electrode liquid inlet of the stack unit 5, and connects the negative electrode liquid outlet of the stack unit 5 to the liquid inlet of the negative electrode liquid tank 7, thereby forming a negative electrode circulation loop between the negative electrode liquid tank 7 and the stack unit 5. A negative electrode liquid pump 9 is provided on the negative electrode pipe 10 between the liquid outlet of the negative electrode liquid tank 7 and the negative electrode liquid inlet of the battery stack unit 5. Under the action of the negative electrode liquid pump 9, the negative electrode electrolyte circulates between the negative electrode liquid tank 7, the negative electrode pipe 10 and the negative electrode liquid flow channel of the battery stack unit 5. The direction of the hollow arrow on the negative electrode pipe 10 is the flow direction of the negative electrode electrolyte.

[0068] As shown in Figure 2, the liquid flow battery cleaning device includes: a detection device, a first foreign matter removal device 6 and a second foreign matter removal device 11. The detection device may include a first detection device 12, which can be connected to the battery stack unit 5 and is configured to detect whether there are foreign matter in the battery stack unit 5. The first foreign matter removal device 6 can be installed between the cathode liquid outlet of the battery stack unit 5 and the liquid inlet of the cathode liquid tank 1, and is configured to adjust the pressure of the cathode circulation loop. The second foreign matter removal device 11 can be installed between the cathode liquid outlet of the battery stack unit 5 and the liquid inlet of the cathode liquid tank 7, and is configured to adjust the pressure of the cathode circulation loop.

[0069] In an exemplary embodiment, the first detection device 12 may be an ultrasonic detector. A timer may be used to record the time when the ultrasonic detector emits a sound wave and the time when the return sound wave is received. The time difference t between the time when the sound wave is emitted and the time when the return sound wave is received is the propagation time of the sound wave. Combined with the propagation speed of the sound wave, the distance between the sound wave emission point and the obstacle can be calculated. For example, assuming that the propagation speed of ultrasound in air is 340 m / s, and the time difference between the time when the ultrasonic detector emits a sound wave and the time when the return sound wave is received is t, the distance s between the sound wave emission point and the obstacle can be calculated according to the following formula 1:

[0070] s = 340t / 2 = 170t, Formula 1

[0071] Formula 1 can be used to determine the actual location of a foreign object within a stack unit, facilitating accurate identification of the fault point. For example, if the foreign object is located in the cathode or anode flow path of the stack unit, the foreign object can be removed using the first or second foreign object removal device.

[0072] In an exemplary embodiment, the ultrasonic detector may be turned on once every first time period t1 to detect foreign objects in the battery stack unit 5 .

[0073] In an exemplary embodiment, the first foreign matter removal device 6 and the second foreign matter removal device 11 may be electric valves, which is not limited in the present application.

[0074] In an exemplary embodiment, the detection device further includes: a second detection device 14 and a third detection device 16. The second detection device 14 can be disposed on the cathode pipe 4 between the cathode liquid pump 3 and the cathode liquid inlet of the stack unit 5, and is configured to detect a first pressure value of the cathode circulation loop. The third detection device 16 can be disposed on the cathode pipe 10 between the cathode liquid pump 9 and the cathode liquid inlet of the stack unit 5, and is configured to detect a second pressure value of the cathode circulation loop.

[0075] In an exemplary embodiment, the second detection device 14 may be a pressure sensor, which may be connected to the positive electrode pipe 4 via the first valve 13 . The third detection device 16 may be a pressure sensor, which may be connected to the negative electrode pipe 10 via the second valve 15 .

[0076] In an exemplary embodiment, the pressure value of the positive electrode circulation loop and the pressure value of the negative electrode circulation loop can be adjusted separately. After determining that there is foreign matter in the battery stack unit 5, it can be first determined whether the location of the foreign matter is in the positive electrode liquid flow channel or the negative electrode liquid flow channel. Taking the foreign matter in the positive electrode liquid flow channel as an example, it can be determined whether the first pressure value of the current positive electrode circulation loop is less than the first threshold value. If it is determined that the first pressure value is less than the first threshold value, the first foreign matter removal device 6 can be controlled to adjust the pressure value of the positive electrode circulation loop to a third pressure value, which is greater than the first pressure value and less than the first threshold value, to flush the foreign matter in the positive electrode liquid flow channel. Similarly, if the foreign matter is in the negative electrode liquid flow channel and the second pressure value is less than the first threshold value, the second foreign matter removal device 11 can be controlled to adjust the pressure value of the negative electrode circulation loop to a fourth pressure value, which is greater than the second pressure value and less than the first threshold value, to flush the foreign matter in the negative electrode liquid flow channel. In an exemplary embodiment, the first threshold value can be the maximum pressure value that the battery stack unit 5 can withstand. In an exemplary embodiment, the fourth pressure value can be equal to the third pressure value.

[0077] In an exemplary embodiment, the pressure value of the positive electrode circulation loop and the pressure value of the negative electrode circulation loop can be adjusted synchronously. After determining that there is foreign matter in the stack unit 5 and the first pressure value and the second pressure value are both less than the first threshold value, regardless of whether the foreign matter is located in the positive electrode liquid flow channel or the negative electrode liquid flow channel, the first foreign matter removal device 6 can be controlled to adjust the pressure value of the positive electrode circulation loop to the third pressure value, and the second foreign matter removal device 11 can be controlled to adjust the pressure value of the negative electrode circulation loop to the fourth pressure value, so that the liquid flow condition of the positive electrode circulation loop is consistent with the liquid flow condition of the negative electrode circulation loop, and crystallization can also be prevented from occurring in the circuit on the side where there is currently no crystallization. In actual applications, the pressure value of the positive electrode circulation loop and the pressure value of the negative electrode circulation loop can be set to be adjusted separately or synchronously as needed, and this application is not limited to this. In an exemplary embodiment, the first threshold value can be the maximum pressure value that the stack unit 5 can withstand. In an exemplary embodiment, the fourth pressure value can be equal to the third pressure value. The details of adjusting the pressure value of the positive electrode circulation loop and the pressure value of the negative electrode circulation loop separately or synchronously can refer to the description of the above embodiment and will not be repeated here.

[0078] In an exemplary embodiment, the flow battery cleaning device further includes a first filter device 17 and a second filter device 19. The first filter device 17 can be disposed on the positive electrode pipe 4 between the liquid inlet of the positive electrode liquid tank 1 and the first foreign matter removal device 6, and is configured to prevent foreign matter from entering the positive electrode liquid tank 1. The second filter device 19 can be disposed on the positive electrode pipe 4 between the liquid inlet of the negative electrode liquid tank 7 and the second foreign matter removal device 11, and is configured to prevent foreign matter from entering the negative electrode liquid tank 7.

[0079] In an exemplary embodiment, the first filter device 17 may be a Y-type filter, the first outlet of which is connected to the liquid inlet of the cathode liquid tank 1, allowing the filtered cathode electrolyte to enter the cathode liquid tank 1. The second outlet 18 of the Y-type filter is configured to receive filtered foreign matter, which can be removed by cleaning the second outlet 18. The second filter device 19 may be a Y-type filter, the first outlet of which is connected to the liquid inlet of the cathode liquid tank 7, allowing the filtered cathode electrolyte to enter the cathode liquid tank 7. The second outlet 20 of the Y-type filter is configured to receive filtered foreign matter, which can be removed by cleaning the second outlet 20.

[0080] In an exemplary embodiment, the flow battery cleaning device may further include a first switch 2 and a second switch 8. The first switch 2 may be disposed on the positive electrode pipeline 4 between the positive electrode liquid pump 3 and the positive electrode liquid tank 1, and the second switch 8 may be disposed on the negative electrode pipeline 10 between the negative electrode liquid pump 9 and the negative electrode liquid tank 7. The first switch 2 may be an electric valve to close the positive electrode pipeline 4 in the event of a malfunction of the positive electrode liquid pump 3, thereby preventing the positive electrode electrolyte from flowing out of the positive electrode liquid tank 1 and facilitating replacement or repair of the positive electrode liquid pump 3. The second switch 8 may be an electric valve to close the negative electrode pipeline 10 in the event of a malfunction of the negative electrode liquid pump 9, thereby preventing the negative electrode electrolyte from flowing out of the negative electrode liquid tank 7 and facilitating replacement or repair of the negative electrode liquid pump 9.

[0081] In an exemplary embodiment, the flow battery cleaning device further includes a fourth detection device (not shown), which is configured to detect whether the working state of the flow battery is normal before the first detection device 12 detects whether there is foreign matter in the battery stack unit.

[0082] In an exemplary embodiment, the flow battery cleaning device further includes a fifth detection device (not shown), which is configured to detect whether the working state of the battery stack unit is normal before the first detection device 12 detects whether there is foreign matter in the battery stack unit.

[0083] In an exemplary embodiment, the flow battery cleaning device may further include a display device (not shown), which may be configured to display various detection results of the detection device and the working status of the flow battery cleaning device.

[0084] In an exemplary embodiment, the liquid flow battery cleaning device also includes an automatic control device (not shown), which can be configured to control the operation of the first foreign matter removal device, the second foreign matter removal device and the display device according to the detection results of the detection device to achieve automatic operation of the above-mentioned liquid flow battery cleaning device.

[0085] An embodiment of the present application also provides a method for cleaning a liquid flow battery, wherein the liquid flow battery includes: a positive electrode liquid tank, a negative electrode liquid tank and a stack unit, wherein the positive electrode liquid tank and the stack unit form a positive electrode circulation loop, and the negative electrode liquid tank and the stack unit form a negative electrode circulation loop; the method includes: using a first detection device to detect whether there is foreign matter in the stack unit; using a first foreign matter removal device to remove foreign matter located in the positive electrode circulation loop, wherein the first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop; and using a second foreign matter removal device to remove foreign matter located in the negative electrode circulation loop, wherein the second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop.

[0086] The flow battery cleaning method provided in the embodiment of the present application, when the first detection device detects the presence of foreign matter in the stack unit, adjusts the pressure value of the positive electrode circulation loop through the first foreign matter removal device, and adjusts the pressure value of the negative electrode circulation loop through the second foreign matter removal device, which can increase the flushing force of the electrolyte in its own circulation loop, and thus can clean out foreign matter in the stack unit. The flow battery cleaning method provided in the embodiment of the present application can timely detect and clean foreign matter such as crystals in the stack unit, can reduce the probability of clogging of the stack unit, help ensure the long-term stable operation of the flow battery, and reduce the maintenance cost of the flow battery.

[0087] The flow battery cleaning method provided in the embodiments of the present application is described below with reference to the accompanying drawings.

[0088] FIG3 is a schematic diagram of a cleaning process using the flow battery cleaning device shown in FIG2 in an exemplary embodiment. FIG3 illustrates an example in which the first detection device is an ultrasonic detector and the second and third detection devices are pressure sensors. As shown in FIG3, the flow battery cleaning process includes:

[0089] S1. Detect the working status of the flow battery.

[0090] Before the flow battery cleaning device officially begins operation, it must ensure that the flow battery connected to the cleaning device is functioning properly. The fourth detection device can be used to detect the operating status of the flow battery. If the operating status of the flow battery is detected to be abnormal, the process proceeds to step S9. If the operating status of the flow battery is normal, the process proceeds to step S2, and the flow battery cleaning device can officially begin operation.

[0091] S2. After t1, turn on the ultrasonic detector.

[0092] In an exemplary embodiment, the ultrasonic detector can be configured to automatically transmit a signal back to the automatic control device upon detecting a foreign object, and otherwise not transmit a signal back. The ultrasonic detector can be turned on once every first time period t1 to perform ultrasonic detection on the battery stack unit and determine whether the ultrasonic detector transmits a signal back. If the ultrasonic detector transmits a signal back, the process proceeds to step S3. If the ultrasonic detector does not transmit a signal back, it indicates that no foreign object is present in the battery stack unit, and the process returns to step S1. In other embodiments, the ultrasonic detector can be kept on continuously, and a check can be performed every first time period t1 to determine whether the ultrasonic detector transmits a signal back. This is not a limitation of the present application.

[0093] S3. Detect the pressure value in the pipeline.

[0094] In an exemplary embodiment, when the ultrasonic detector detects the presence of foreign matter in the battery stack unit, the first pressure value of the positive electrode circulation loop detected by the second detection device and the second pressure value of the negative electrode circulation loop detected by the third detection device can be read, and it can be determined whether the first pressure value is less than the first threshold value and whether the second pressure value is less than the first threshold value. If it is determined that the first pressure value is greater than or equal to the first threshold value or the second pressure value is greater than or equal to the first threshold value, the process jumps to step S8. If it is determined that the first pressure value is less than the first threshold value and the second pressure value is less than the first threshold value, the process jumps to step S4.

[0095] S4. Increase the pressure in the pipeline and continue for t2, during which the ultrasonic detector is kept on.

[0096] In an exemplary embodiment, if the first pressure value is less than the first threshold value and the second pressure value is less than the first threshold value, it indicates that the pressure in the pipeline remains at a normal level, and foreign matter can be flushed out by adjusting the pressure. The first foreign matter removal device can be controlled to adjust the pressure in the positive electrode circulation loop to a third pressure value and maintain the third pressure value for at least a second time period t2, wherein the third pressure value is greater than the first pressure value and less than the first threshold value. The second foreign matter removal device can be controlled to adjust the pressure in the negative electrode circulation loop to a fourth pressure value and maintain the third pressure value for at least a second time period t2, wherein the fourth pressure value is greater than the second pressure value and less than the first threshold value. The pressures in the positive and negative electrode circulation loops can be adjusted independently or simultaneously. The ultrasonic detector remains on during the process of increasing the pipeline pressure and during a second time period t2 after the pressure increase is complete to monitor whether foreign matter has been removed. By adjusting the pressures in the positive and negative electrode circulation loops, the pressure of the electrolyte flow is increased, and the impact force generated by the electrolyte flow is greater, thereby flushing foreign matter out of the stack cells. The specific adjustment method and adjustment process can be referred to the description in the above embodiment and will not be repeated here.

[0097] In other embodiments, the ultrasonic detector can be set not to work continuously, but after adjusting the pressure value in the positive circulation loop and the negative circulation loop and maintaining the pressure value for the second time period t2, the ultrasonic detector is turned on for detection. Even if the foreign matter is flushed away during the pressure adjustment period, the electrolyte can still be maintained to flush the positive circulation loop and the negative circulation loop at a high speed for the second time period, ensuring that the foreign matter is cleaned more thoroughly.

[0098] After step S4, if it is determined that the ultrasonic detector no longer returns a signal, the process proceeds to step S5. If it is determined that the ultrasonic detector still returns a signal, the process proceeds to step S6.

[0099] S5. The stack unit is cleaned.

[0100] Since the ultrasonic detector no longer sends back a signal, it can be determined that the foreign matter has been removed, and the process then jumps back to step S1.

[0101] In an exemplary embodiment, after the stack unit is cleaned, foreign matter will be intercepted by the first filter device or the second filter device, and the first filter device and the second filter device can be cleaned. When the first filter device and the second filter device are Y-type filters, the filtered foreign matter can be directly cleaned from the second end outlet of the Y-type filter.

[0102] In an exemplary embodiment, it can be set to clean the first filter device or the second filter device once after the stack unit is cleaned multiple times. In an exemplary embodiment, a number threshold can be set in advance, and the first filter device or the second filter device is cleaned once after the number of cleanings reaches the number threshold. The size of the number threshold can be set as needed, and this application does not limit this. For example, the automatic control device can record the number of times the stack unit is currently cleaned, and the number of cleanings of the positive circulation loop and the negative circulation loop can be counted separately. After the number of cleanings of the positive circulation loop reaches the set number threshold, the first filter device is cleaned once, and after the number of cleanings of the negative circulation loop reaches the set number threshold, the second filter device is cleaned once. The number threshold of the positive circulation loop and the number threshold of the negative circulation loop can be the same or different. The automatic control device can display relevant information (the number of times the stack unit completes cleaning and the time of each cleaning, the number threshold and the time when the filter device was last cleaned, etc.) on a display device to facilitate the staff to perform cleaning operations. The specific operations and reminder methods for cleaning the first filter device or the second filter device can be set as needed, and this application does not limit this.

[0103] S6. Replace the battery stack unit.

[0104] Since the ultrasonic detector continues to send back signals, it can be determined that the foreign object cannot be removed and the battery cell can only be replaced. After replacing the battery cell, jump to step S7.

[0105] S7. Check whether the working status of the battery stack unit is normal.

[0106] In an exemplary embodiment, the fifth detection device may be used to detect the working state of the battery stack unit. If the working state of the battery stack unit is normal, the process jumps back to step S1. If the working state of the battery stack unit is abnormal, the process jumps to step S9.

[0107] S8. Shutdown for maintenance.

[0108] If the first pressure value is greater than or equal to the first threshold or the second pressure value is greater than or equal to the first threshold, it indicates that the operating pressure of the flow battery itself is too high and shutdown maintenance is required. After the shutdown maintenance is completed, the process can jump back to step S1.

[0109] S9. The display device displays the feedback signal.

[0110] When the flow battery is operating abnormally, a first feedback signal is generated, and the detected abnormal state is displayed on a display device, so that the staff can further investigate the source of the fault.

[0111] When the working state of the battery stack unit is abnormal, a second feedback signal is generated, and the detected abnormal state is displayed on the display device, so that the staff can further investigate the source of the fault.

[0112] In an exemplary embodiment, the processing status of steps S2 to S6 and S8 can also be displayed on the display device. For example, each time the ultrasonic detector is turned on in step S2, the detection result can be displayed. After the pressure value in the pipeline is detected in step S3, the display device can display the current pressure value in the positive and negative pipelines. In step S4, the pressure value level in the pipeline can be updated in real time during the process of increasing the pressure value in the pipeline, and the detection result of the ultrasonic detector can be displayed. In step S5, the completion of the stack unit cleaning can be displayed to facilitate staff to understand the operation status of the liquid flow battery. In step S6, a prompt can be provided that the stack unit is currently being replaced. In step S8, a prompt can be provided that the battery is currently shut down for maintenance. The display content of the display device can be set as needed, and this application does not impose any restrictions on this.

[0113] The liquid flow battery cleaning method of the embodiment of the present application is applied to the liquid flow battery cleaning device described in the above embodiment. The role and effect of each step can be found in the description of the above-mentioned liquid flow battery cleaning device, which will not be repeated here.

[0114] An embodiment of the present application also provides a liquid flow battery cleaning system, comprising a liquid flow battery and the liquid flow battery cleaning device described in the above embodiment.

[0115] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art to which the present invention pertains may make any modifications and variations in the form and details of the embodiments without departing from the spirit and scope of the present invention.

Claims

1. A liquid flow battery cleaning device, the liquid flow battery comprising: A positive electrode liquid tank, a negative electrode liquid tank and a battery stack unit, wherein the positive electrode liquid tank and the battery stack unit form a positive electrode circulation loop, and the negative electrode liquid tank and the battery stack unit form a negative electrode circulation loop; characterized in that the liquid flow battery cleaning device comprises: a detection device, a first foreign matter removal device and a second foreign matter removal device, wherein the detection device comprises a first detection device; The first detection device is configured to detect whether there is a foreign object in the battery stack unit; The first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop; The second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop.

2. The liquid flow battery cleaning device according to claim 1, characterized in that: The first detection device is configured to detect whether there is a foreign object in the battery stack unit every first time period.

3. The liquid flow battery cleaning device according to claim 1, characterized in that: The detection device also includes a second detection device and a third detection device; The second detection device is configured to detect a first pressure value of the positive electrode circulation loop, and the third detection device is configured to detect a second pressure value of the negative electrode circulation loop; The first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop to a third pressure value when the first pressure value is less than a first threshold value; the third pressure value is greater than the first pressure value and less than the first threshold value; The second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop to a fourth pressure value when the second pressure value is less than the first threshold; the fourth pressure value is greater than the second pressure value and less than the first threshold.

4. The liquid flow battery cleaning device according to claim 1, characterized in that: The liquid flow battery cleaning device also includes a first switch and a second switch, wherein the first switch is arranged on the positive electrode circulation loop and is configured to open or close the positive electrode circulation loop; the second switch is arranged on the negative electrode circulation loop and is configured to open or close the negative electrode circulation loop.

5. The liquid flow battery cleaning device according to claim 1, characterized in that: The flow battery cleaning device also includes a first filter device and a second filter device; The first filter device is connected to the positive electrode circulation loop and is configured to prevent the foreign matter from entering the positive electrode liquid tank; the second filter device is connected to the negative electrode circulation loop and is configured to prevent the foreign matter from entering the negative electrode liquid tank.

6. The liquid flow battery cleaning device according to claim 5, characterized in that: The detection device further includes a fourth detection device, which is configured to detect whether the working state of the flow battery is normal before the first detection device detects whether there is a foreign object in the battery stack unit.

7. The liquid flow battery cleaning device according to claim 6, characterized in that: The liquid flow battery cleaning device also includes a display device; the display device is configured to display whether the working state of the liquid flow battery is normal according to the detection result of the fourth detection device.

8. The liquid flow battery cleaning device according to any one of claims 1 to 7, characterized in that: The flow battery cleaning device also includes an automatic control device; The automatic control device is configured to control the operation of the first foreign matter removal device, the second foreign matter removal device and the display device according to the detection result of the detection device.

9. A method for cleaning a flow battery, characterized in that: The liquid flow battery comprises: a cathode liquid tank, a cathode liquid tank and a battery stack unit, wherein the cathode liquid tank and the battery stack unit form a cathode circulation loop, and the cathode liquid tank and the battery stack unit form a cathode circulation loop; the method comprises: Using a first detection device to detect whether there is foreign matter in the battery stack unit; removing foreign matter in the positive electrode circulation loop by using a first foreign matter removal device, wherein the first foreign matter removal device is configured to adjust the pressure of the positive electrode circulation loop; A second foreign matter removal device is used to remove foreign matter located in the negative electrode circulation loop, and the second foreign matter removal device is configured to adjust the pressure of the negative electrode circulation loop.

10. A liquid flow battery cleaning system, characterized in that: The invention comprises a liquid flow battery and a liquid flow battery cleaning device as claimed in any one of claims 1 to 8.

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